For a general washing machine installed in a common home or a laundromat, the laundry will be biased in a dewatering tub during dewatering, causing vibrations and noises. Depending on the location of the washing machine and the surrounding environment thereof, troubles may occur due to the vibrations and the noises. In addition, when the laundry is greatly biased during the dewatering, the eccentricity of the dewatering tub during the rotation becomes greater, and thus a large torque is required for the rotation. Accordingly, the dewatering operation cannot be started.
In view of the above, the following first technique may be employed: an unbalance amount and an unbalance position of the laundry inside the washing tub are detected during the dewatering; when there is imbalance, the washing tub is braked to stop rotating to reduce the centrifugal force so that a mass of laundry causing the imbalance drops and is dispersed by gravity.
In addition, the following second technique may be employed: it is determined whether there is imbalance in the washing/dewatering tub during a low-speed rotation; when the imbalance is detected, to eliminate the imbalance, the motor is stopped, and water is injected to the washing/dewatering tub to release the mass of laundry.
However, for the first technique, unbalance detection and dispersion operation are performed only when the dewatering tub is rotated at a low speed, and there is a possibility that the unbalance may occur again due to factors such as the type of the laundry after a high speed rotation of the dewatering tub is started.
Moreover, for the first and second techniques, since the rotation of the dewatering tub is decelerated or stopped when the imbalance is detected, a start-up power is required every time the dewatering operation is repeated, causing an increase in power consumption. Furthermore, with the second technique, in addition to the increase in power consumption, a problem that the amount of water used increases exists.